[llvm] [loop-idiom] Forget outer loop scev when loop-idiom introduces memset… (PR #150916)

[Nikita Popov via llvm-commits]

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@@ -7421,6 +7422,13 @@ ScalarEvolution::getLoopProperties(const Loop *L) {
       if (auto *SI = dyn_cast<StoreInst>(I))
         return !SI->isSimple();
 
+      // Check if the function accesses inaccessible memory.
+      if (auto *CI = dyn_cast<CallInst>(I)) {
+        auto ME = CI->getMemoryEffects();
+        if (!isModSet(ME.getModRef(IRMemLocation::InaccessibleMem)))
+          return false;
+      }
+
       return I->mayThrow() || I->mayWriteToMemory();
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nikic wrote:

mayThrow() needs to be checked first, otherwise the early exit may bypass it.

https://github.com/llvm/llvm-project/pull/150916